Kathryn Bigelow is talking about crossing the border from Jordan into Iraq while filming her latest movie, The Hurt Locker. "We were so close: five kilometres. If you'd just gone down that road five more minutes you could get there. But we had some security guards with us who said they couldn't guarantee our safety, because of snipers. We thought long and hard about it."

Making the film was a physically demanding job, shooting in Jordan in sweltering temperatures, often in isolated desert areas, with heavy equipment; the conditions got the better of many of her crew members. Characteristically, Bigelow wanted to get that bit closer to the danger zone. She was in her element, she says: "I loved making this movie. I'm definitely not drawn to shooting on a stage, I'm just not. If we'd financed this under more conventional methods, I can't imagine a studio would have allowed us that freedom. But it's a movie about the Middle East and, call me crazy, I wanted to shoot it in the Middle East. I don't think Arizona would have been quite right."

Bigelow is often characterised as the toughest director out there. Not just for her intrepid spirit, but also for the high-adrenaline content of her work. She is a woman operating in the most macho of genres – action cinema – and her films deal with intense, high-testosterone environments: biker gangs (her debut The Loveless), cops (Blue Steel), extreme sports junkies (Point Break), submarine crews (K19: The Widowmaker), and now, in The Hurt Locker, a bomb disposal unit in Baghdad. How's that for tough? On paper, she sounds like the sort of woman who drinks men under the table having first beaten them at arm-wrestling and a Hummer rally. In person, though, she's tall and waif-like, gently spoken and regally handsome. She is 57, but looks a decade younger, and her hands make graceful movements in the air as she talks.

The only time the hands stop and the arms fold is when I ask her about being a woman in such masculine environments. "You know . . . I don't know," she hesitates. "I think there's a certain degree of irrelevance to it, and my hope is that it will become more irrelevant the more women enter film-making, but . . . I don't even know how to answer that." One suspects she has got by in the company of so many swaggering males less by arm-wrestling them than by simply charming them into submission. "Am I a 'woman of action'?," she ponders. "I don't think of myself that way. Certainly not for any reason other than authenticity. The nature of this film was so reportorial – if you don't immerse yourself, how are you going to tell the story responsibly?"

Released in the US in June (and out here next week), The Hurt Locker is already being talked of in Oscar terms and has been hailed as the best Iraq movie yet. Not that it's had much competition: of the slew of Iraq-related movies so far, none have exactly troubled the box office or the awards panels. Some, like Brian de Palma's Redacted, have been fiercely condemned for their apparent disloyalty to the US military. Most, like Lions for Lambs, In the Valley of Elah, Grace Is Gone, and Rendition have been labelled the work of anti-war Hollywood liberals who have no idea what they're talking about. But The Hurt Locker was written from first-hand ­ experience by Mark Boal, a reporter who was embedded with the US Army's Explosive Ordnance Disposal squad in Baghdad in 2004. As such, it is exacting in its detail, persuasively authentic and almost entirely free of the usual "war movie" baggage (no big speeches, no epic battles, no clear winners and losers). Instead, the film stays focused on a three-man bomb squad, and in particular their sergeant (Jeremy Renner), who seems only fully functional when in the face of danger.

More problematically, The Hurt Locker is also devoid of any obvious political angle. With its broadly sympathetic portrayal of the military and lack of explicit comment on the wider conflict, some critics have accused it of not being anti-war enough, or even labelled it as propaganda. "The Hurt Locker is one of the most effective recruiting vehicles for the US Army that I have seen," US critic Tara McKelvey wrote in July, for example.

Bigelow will not be drawn on her, or the film's, politics. "I think it's an opportunity to look at the individual in a very difficult situation," she says, choosing her words with care. "And to look at these men who have arguably the most dangerous job in the world, but do it voluntarily, and to begin to unpack that psychology and perhaps make the conflict less abstract. That creates an environment for an informed opinion. What's been really gratifying is that people have come up to me and said, 'I had no idea what was going on in Iraq. Thank you for shedding some light on it.'"

When I ask her about her politics from a slightly different angle – did she set out to make an apolitical film? – she gives what I later realise is essentially the same answer: "The film is looking at the experience of the soldier and trying to put you into those boots – that lonely walk towards what the rest of the world is running from," she concludes. "You can spin that however one wants to spin it."

There are potential clues as to Bigelow's political leanings in, for instance, the film's introductory quote: "The rush of battle is often a potent and lethal addiction, for war is a drug." This comes from a book by war reporter Chris Hedges, a self-professed "socialist" and a fearless critic of the Iraq war. Or from the fact that the only songs on the soundtrack are four tracks from Rio Grande Blood, the 2006 album by industrial metal group Ministry. The album features a ­ caricature of George W Bush on the cover and features a cut-up speech that has the ex-president saying: "I'm a dangerous, dangerous man with dangerous, dangerous weapons."

But if Bigelow's sole objective was to "put you in those boots" with The Hurt Locker, she succeeds hands-down. Shot verité-style with hand-held cameras, her film is an uncannily immersive experience. Bigelow mentions a scene where a soldier has to clean the blood off a magazine cartridge in the middle of an unbearably tense, long-distance sniper shootout. "Use spit," his sergeant tells him; but his mouth is so dry he cannot get the job done. "I've had people tell me that when they were watching him, they were creating saliva in their own mouths," she says. "That's a pre-conscious response."

This is Bigelow's eighth movie in more than 30 years, and although she has had her fair share of failures, nobody would deny that she does action extremely well. Her best known films, Point Break and Strange Days, succeeded because they, too, elicited that visceral response; she calls it "experiential". Point Break featured two of the least cerebral actors in the business – Keanu Reeves and Patrick Swayze – but you bought its absurd plot (an undercover agent falls under the spell of a Zen-spouting, bank-robbing surfer) because the action scenes were so utterly compelling. Similarly, Strange Days, starring Ralph Fiennes (who makes a cameo in The Hurt Locker) hinges on the sci-fi premise of "jacking in" – recording thrilling human experiences, so as to enable others to live them vicariously. It addressed the allure of immersive cinema, and succeeded in replicating it, too, with its subjective camera angles.

Strange Days was written and produced by James Cameron, to whom Bigelow was briefly married. She won't talk about him, though they still speak to each other. He encouraged her to make The Hurt Locker, he has said, and describes her as having "a pitch-perfect ear for bullshit. She knows when something is false."

Bigelow didn't start out wanting to make movies. Her childhood ambition was always to be a painter, and she fulfilled it with apparent ease. California-born, she studied at the San Francisco Art Institute, then moved to New York in the mid-1970s, where she studied under Richard Serra and Susan Sontag. She began to move away from painting, and fell in with conceptual artists such as Lawrence Weiner and the British artists' group Arts and Language. "They were really interested in working against the commodification of culture, looking at how art works within the art itself."

This led to her studying and making films. Somewhat prophetically, her first student film was a 17-minute short of two men punching each other while respected semioticians commented on the seduction of cinematic violence. All her preoccupations were there: gender, genre, action. "Then the ideas just got longer, and I began to embrace narrative." Her first feature, The Loveless, starring Willem Dafoe in his first role, revelled in the homoerotic fetishism of 1950s biker gangs. Its 1987 follow-up, Near Dark, has became a cult classic – a spare, stylish, violent fusion of western, horror and fairy tale, following a roving Manson-like family of white-trash vampires. "I think my art background helped enormously because it gives you an innate sense of space and composition," she says. "Even working on a two-dimensional canvas . . . if you've got strong blocks of colour there . . ." Again, she lets her hands finish the sentence. "It's not that there are rules, but there's a sense of balance and tension. Both things can be happening if you handle them in a certain way. So I think taking those same precepts and instinctually applying them to space is what happened."

Perhaps people have been barking up the wrong tree in trying to pin down Bigelow's politics, or even in attempting to read The Hurt Locker as a political movie. In the end, it is less concerned with the Iraq war in particular than with war in general, and its effects on the minds and bodies of those engaged in it. In other words, it's as much an art film as a war film – an attempt to render the abstract into something tangible. On close inspection, it is almost formally abstract, too: a series of loosely linked, almost interchangeable moments of high tension.

The fact that she has succeeded in making a film so open to opposing interpretations – and yet accessible, internally consistent and commercially viable – is encouraging. Her next project, she says, will be another collaboration with Mark Boal, set on the border between Brazil, Argentina and Paraguay, an area of organised crime and terrorist activity – yet another danger zone. First, she says, she has to get Hurt Locker out of her system. "You have to disengage at some point in order to be fresh. I'm still disarming bombs".